Strapping apparatus for packing straps



June 27, 1967 K. E. T. SELLMAN STRAPPING APPARATUS FOR PACKING STRAPS 2 Sheets-Sheet 1 Filed Jan. 6, 1965 IN VEN TOR. K4,?! [Vi/P7 7525554001 June 27, 1967 5 T, SELLMAN 3,327,619

STRAPPING APPARATUS FOR PACKING STRAPS Filed Jan. 6, 1965 2 Sheets-Sheet 2 FIG.3

yd Z5 2 FIG.5 ZQ If 1 llllllllll ll HHHIIIIIH llIlllllllIllllllllllllllll 2 INVENTOR. //fl/F fnwr 5P5 fizz/MM United States Patent 3,327,619 STRAPPENG APPARATUS FOR PACKING STRAPS Karl Evert Tore Sellman, Hagersten, Sweden, assignor to Lennart Reinhold Kalb, Alters Rune, Sweden Filed Jan. 6, 1965, Ser. No. 423,804 6 Claims. (Cl. 100-29) Strapping apparatus are utilized for strapping a packing, such as a case, with a metal strap, the ends of which after tightening of the strap are fixed to each other by punching locking tongues in the strap or by a seal. The tightening of the strap is performed by means of an advancing wheel which tightens one end part of the strap by advancing this end part in relation to the other end part of the strap. Punching of the locking tongues is performed by punching means movable towards a stationary member. Hitherto the advancing wheel and the punching means always have been arranged side by side of each other, that is to say at a certain mutual distance in the longitudinal direction of the strap. This means that the base plate of the strapping apparatus becomes relatively long and that the strap easily will slacken when the strapping apparatus is removed after tightening and interlocking of the ends of the strap. This risk is particularly predominating as regards relatively small casings.

It is known to perform the punching on one side of the advancing wheel only which, however, causes the inconvenience that a very long base plate has to be utilized. The size of the base plate will increase still more if the strap has to be cut and secured at the same side of the advancing wheel and a long interspace prevails between the devices which perform these functions.

The primary object of the present invention is to avoid the inconveniences now referred to. The invention relates to the type of strapping apparatus which comprises advancing wheel means for tightening the strap and punching means including a punching member movable towards a stationary punching member for punching at least two locking tongues in the strap. The invention is substantially characterized in that the movable member is adapted to punch at least two longitudinally spaced locking tongues in the strap, one such tongue being formed in the strap on one side of the advancing wheel means and the other such tongue being formed in the strap on the other side of the advancing wheel means, and in that the movable member of the punching means and the advancing wheel means are provided in or adjacent to one and the same vertical longitudinal plane.

An embodiment of an apparatus according to the invention is shown in the accompanying drawings, in which:

FIG. 1 is a vertical section showing the principal parts of the apparatus according to the invention.

FIG. 2 is a plan view of the stationary port-ion of the apparatus.

FIG. 3 is a vertical section perpendicular to FIG. 1.

FIG. 4 is a bottom view taken on the line IV-IV in FIG. 1.

FIG. 5 is a diagrammatic plan view of the ends of the strap fastened by the apparatus.

The apparatus has a support 1 provided with a projecting base plate 2. The packing strap is Wrapped in usual manner around the packing to be strapped and the strap parts are inserted in the interspace between the support and the base plate thereof, in which said strap parts are to be tightened and then secured to each other. In the support 1 a movable punch die 3 is guided in a vertical guide and is kept in its position by a clamp 4 screwed to the support. The lower edge 3a (see also FIG. 4) of the punch die has a punching surface for cooperation with a stationary punching member 5 on the base plate 2. The punching surfaces are designed so as to cause the strap sections 6, 6a (FIG. 5) inserted between the punching members 3a, 5 and placed on each other to punch circular arcuate tongues 7, 7a integral with the strap sections into said strap sections and to interlock them to each other. The punch die further has a cutting edge 8 cooperating with a shear-type cutter 9 for cutting one of the strap sections after the interlocking operation.

The punch die 3 is operated by a bar 10 in the support pivoted on a pin 11 and by means of its beak-shaped end 12 cooperating with a link 13 which is pivoted on a pin 14 together with a roller 15 in the punch die 3. The bar 10 is provided with an eccentric surface 16 engaging the roller 15. When the bar 10 is turned in counterclockwise direction as indicated by arrow P the eccentric surface 16 is pushed towards the roller 15 so as to press down the movable punch die 3 against the stationary punching member 5 for effecting punching and cutting of the strap sections. The bar 10 can be turned in this direction until a shoulder 17 on the bar abuts an adjustable stop 18 on the support. Turning of the bar in the opposite direction causes the link 13 to lift the punch die 3 back into its top position.

After the punching operation is completed the strap sections are to be lifted from the stationary punching member 5. This action is performed by lifting means 19 placed in separate apertures in the die, being bent over at their top ends 19a to be pivoted into the punch die 3 and at their lower ends 19b being bent over in a similar manner to seize and lift the strap from the stationary punching member 5 when the punch die moves in upward direction.

After the strap having been wrapped round the casing the upper strap section first has to be tightened. This is performed by means of a grooved wheel 20 comprising two axially spaced parts provided on a shaft 21. FIG. 3 clearly shows that the movable punching die together with its punching surface 3a is located between the parts of the advancing wheel, that is to say in the advancing wheel on opposite sides of the shaft 21 which is rendered possible by a U-shaped recess 21a in the die. Accordingly the die is mainly located in the same vertical plane as the advancing wheel instead of being arranged on the side of the advancing wheel as hitherto customary. Thus, the punch and the advancing wheel act on the same side of the strap. The shaft 21 is eccentrically journalled in a bushing 22. The bushing may be turned by a bar (not shown) in order to lower the advancing wheel 20 towards the strap, the lower section of which is pressed against a stationary grooved base 23. Subsequently the advancing wheel is tightened so as to advance the upper section of the strap in forward direction and to tighten it. Then the aforementioned punching and cutting operation follows.

From the statements above the great advantage becomes evident of providing the advancing wheel in close proximity to the punching tool; the latter being located between the two parts of the advancing wheel and thus mainly in the same vertical plane as the advancing wheel so that the base plate 2 can be made very short, viz. not much longer than the punch itself. It is also advantageous as shown in FIG. 5 to design the punching means so as to punch circular .arcuate interlocking tongues in the strap instead of angular ones in order to improve the strength of the strap as compared with tongues of angular shape. In addition thereto the locking friction between each pair of tongues is improved in the two strap parts and also the retaining action in backward direction;

What I claim is:

1. A strapping apparatus for applying a strap to a packing, said apparatus comprising two punching means spaced a short distance longitudinally of the strap, each of said punching means having cooperating stationary and movable punching members for punching at least one looking tongue in the strap, and a strap advancing wheel means disposed in general longitudinal alignment with said two punching means and longitudinally between them.

2. A strapping apparatus according to claim 1, wherein the strap advancing wheel means comprises a strap engaging wheel disposed with its axis transverse to the length of the strap and generally mid-way between the two punching means lengthwise of the strap.

3. A strapping apparatus according to claim 1, wherein said advancing wheel means comprises a strap advancing wheel of an intermediate body and two external flanges, and wherein said movable punching member of each of said two punching means is located between said external flanges of the strap advancing wheel.

4. A strapping apparatus according to claim 1, comprising a reciprocable plunger, and means for reciprocating the plunger, the movable members of the two punching means being connected to the plunger to reciprocate therewith.

5. A strapping apparatus according to claim 4, comprising a support having guide means for the plunger,

said guide means being located approximately in alignment with the advancing wheel means, and means adjustably mounting the advancing wheel means on the support for selective engagement with and withdrawal from the strap.

'6. An apparatus according to claim 1, wherein the punching members of each of said punching means are provided with punching surfaces for punching tongues. with lateral edges in said strap.

References Cited UNITED STATES PATENTS 2,040,576 5/1936 Timmerbeil 14093.2

FOREIGN PATENTS 20,966 10/ 1935 Australia. 157,093 6/ 1954 Australia. 147,656 11/1954 Sweden.

OTHER REFERENCES German printed application Z 3,670, April 1956.

LOUIS O. MAASSEL, Primary Examiner. 

1. A STRAPPING APPARATUS FOR APPLYING A STRAP TO A PACKING, SAID APPARATUS COMPRISING TWO PUNCHING MEANS SPACED A SHORT DISTANCE LONGITUDINALLY OF THE STRAP, EACH OF SAID PUNCHING MEANS HAVING COOPERATING STATIONARY AND MOVABLE PUNCHING MEMBERS FOR PUNCHING AT LEAST ONE LOCKING TONGUE IN THE STRAP, AND A STRAP ADVANCING WHEEL MEANS DISPOSED IN GENERAL LONGITUDINAL ALIGNMENT WITH SAID TWO PUNCHING MEANS AND LONGITUDINALLY BETWEEN THEM. 